Control apparatus for radiobeacon systems



y 9, 1939- N. H. CLOUGH 2,157,690 I CONTROL APPARATUS FOR RADIOBEACON SYSTEMS Filed Oct. 23, 1937 ---'-===Z INVENTOR.

g NEW 0M5 H. CLOUGH .2. 5/ BY 7 MW H7, ATTORNEY.

Patented May 9, 1939 UNITED STATES PATENT orrics coN'rnoL APPARATUS FOR RADIOBEACON SYSTEMS Newsome Henry Clough, London, England, assignor to Radio Corporation of America, a corporation of Delaware Application October 23, 1937, Serial No. 170,572 In Great Britain October 26, 1936 4 Claims. (Cl. 175-320) This invention relates to electrical control apeach winding may actually operate the said conparatus and has for its object to provide electrical tacts or, in order to reduce the load upon the control apparatus adapted to control radio transwinding, each winding may operate directly only mitting or other apparatus in such manner as to a single pair of contacts which are in the circuit 5 produce repeatedly desired signals or combinaof the winding of a subsidiary relay which oper-' 5 tions of signals. ates the said plurality of contacts, there being The invention is of wide application but an imthus one subsidiary relay associated with each of portant application of the said invention is to the first mentioned relay windings.

navigation aiding radio transmitters of the equi- The invention is illustrated in the accompanysignal and similar types wherein predetermined ing drawing in which: 10 combinations of signals are required to be re- Figure 1 shows diagrammatically a typical cirpeatedly and periodicallytransmitted, For exciut arrangement adapted to control a pair of ample, in one well known type of equi-signal radio transmitters for use in an equi-signal transmitter two directional overlapping radiations beacon of the complementary signal type;

are transmitted to produce an equi-signal zone Fig. 2 show a modification of the circuit ar- 15 in the overlap area, one of said radiations being rangement, and keyed or modulated with one and the other with Fig. 3 shows an alternative feature which may another of two complementary or interlocking be used under certain conditions. signals, for example, the Morse letters A and N Referring to Fig. 1, there are four relay wind- 0 or the Morse letters E and T. In known apparaings WI, W2, W3 and W4. Each relay winding is tus of this kind it has been usual to generate the shunted by a series circuit consisting of a concomplementary signals by means of cam-operated denser and a neon or other g w discharge tube switches or commutators driven by clockwork for inseries, the condensers. being marked Cl, C2, C3 other rotary driving means. The present invenand C4, and the tubes being marked NI, N2, N3

tion, as will be seen later, provides apparatus and N4. Chargingresistances RI',R2,R3 and R4 25 whereby desired signals may be repeatedly and are provided, one for each condenser, the chargperiodically obtained without the use of clockwork ing potential being obtained from a source (not or other rotary machinery and by apparatus in,- shown) which is connected at HTI, I-IT2. In the volving the minimum of mechanically moving arrangement illustrated each relay is arranged to parts. operate four pairs of contacts directly without the. 30

According to the main feature of this invention, interposition of a subsidiary relay, but as 'hereelectrical control apparatus suitable for use for inbefore stated, indirect operation may be rethe purpose specified comprises a plurality of sorted to. The contacts marked MI, M2, M3 and condensers each having its own charging circuit M4 are holding" circuit contacts for the various designed to permit the appropriate condenser to relays; the contacts marked Bl, B2, B3 and B4 charge to a predetermined voltage in a predeare releasing" contacts for the various relays; termined time, and a glow discharge tube in the contacts marked Sl, S2, S3 and S4 are startseries with a relay winding in shunt with each ing contacts; and the contacts marked Yl, X2, condenser, each relay winding controlling the Y3, and X4 are operating contacts.

0 operation of a plurality of contacts which include It is thought that the operation of the arrange- 4( contacts for exercising the desired control funcment will to a large extent be understood from the tions and at least two pairs of additional configure itself. Ignore for the moment the contacts tacts, said additional contacts being included in SI, S2, S3 and S4 and suppose that one of the recircuit with the relay windings and the additional lays, for example, the relay'having winding WI,

contacts on the respective relays being interis moved by hand into its energized or operated connected so that the condensers charge one at position, The contacts Ml are thus closed and a time in predetermined sequence the complethe relay winding Wl will maintain itself in tion'of the charge in any one condenser to a voltenergized condition throughthe said contacts Ml. age sufficient to break down the associated glow Simultaneously the condenser C4. will commence discharge lamp causing (through the energization to charge through a circuit including the re- 5 of the associated relay) a breaking of the enersistance R4the contacts MI .and the contacts B4. gizing circuit for the relay which was last When the potential across condenser C4 reaches energized. a sufllcient value to break down the tube N4, the

The control by each relay winding of the assaid condenser will discharge through the tube sociated plurality of contacts may be direct, i. e., N4 and winding W4 in series, operating the relay i in question and accordingly closing the contacts M4 and opening the contacts B4. The opening of contacts B4 opens the circuit for the winding WI and the closing of the contacts M4 closes a holding circuit for the winding W4. Upon examination of the figure it will be seen that a similar interlocking action applies between all the relays, which will close, one at a time, in succession. The next relay to close will be the relay having winding W3; the next relay to close will be that with winding W2 and so on with cyclic repetition.

In practice it is obviously inconvenient to start the action by closing a relay by hand, and accordingly a starting relay having a winding S is provided. This relay S operates to close contacts K thus completing a circuit across the D. C. terminals HTI and HT2, through the winding of relay W3. The operating circuit for relay S may be traced across the terminals HTI and HT2, and is completed only when all of the series-connected contacts SI', S2, S3 and S4 are simultaneously closed, that is, when the operation of the system is to be started. During sequence operations of the device the holding circuit for each relay is caused to look its own relay and to deionize the associated glow tube by applying positive potential to the cathode thereof. .Since each pair of holding circuit contacts for one re- ,lay is in series with a pair of contacts which are opened by a subsequently operable relay, it will be clear that the locking circuits are arranged to be closed and opened in succession, thereby producing a sequential action of the relays and associated glow tubes.

The contacts X4, X2, Y3 and YI are operating contacts, X4 and X2 being in parallel across the leads X (which are the control leads for one transmitter-mot shown) and the contacts Yl and Y3 being in parallel across the leads Y (which are the control leads for the other transmitter-not shown). The supply voltage, the various charging circuits and the glow discharge tube ignition voltages'are so chosen that the vari-' ous charging times are of the desired values appropriate to the signals desired. I The operating speed of the whole arrangement can obviously be varied by varying the potential applied at the terminals HTI, HT2.

In Fig. 1 the various relay contacts are shown in their normal positions; that is to say, in the positions they occupy when the operating windings associated therewith are not energized.

-Fig. 2 of the accompanying drawing shows a modification of the arrangement shown in Fig. 1. In this modification each relay operates either directly as shown, or through a subsidiary relay, five pairs of contacts instead of, as in Fig. 1, four pairs of contacts. Of these contacts X4, Y3, X2, Yl correspond to and serve the same purpose as the correspondingly referenced contacts of Fig, 1. The other contacts are marked IKI, lK2, IK3, IK4 for relay winding WI; 2Kl, 2K2, 2K3, 2K4 for winding W2; 3Kl, 3K2, 3K3, 3K4 for winding W3; and 4Kl, 4K2, 4K3 and 4K4 for winding W4, those with the sufiix "1 e. g., IKI, 2KI, etc., being holding circuit contacts (corresponding to, the contacts Mof Fig. 1), all other "K" contacts being releasing contacts, (corresponding to contacts B of Fig. 1). As will be seen, assuming that all the relays are in deenergized position (that shown) all the condensers Cl, C2, C3, C4 will commence to charge as soon as positive potential is applied at HTI. The charging circuit for CI includes IK2, 4K3

and 3K4; that for C2 includes 2K2, IK3 and 4K4; that for C3 includes 3K2, 3K3, and IK4; and that for C4 includes 4K2, 3K3 and 2K4. One discharge device N 1, N2, N3 or N4 will breakdown first and the associated relay winding will accordingly be energized. Suppose the first to breakdown is N3. Then relay W3 will be energized and will maintain its own circuit by closing 3Kl breaking all the charging circuits except one by opening contacts 3K2, 3K3, and 3K4. The one charging circuit left complete will be that for condenser C2. When condenser C2 is charged sufficiently to breakdown device N2 the relay winding W2 is energized, the maintain circuit for W3 is broken at 2K2, the circuit of winding W2 is maintained at 2Kl andthe charging circuit for C2 is broken at 2K2, the charging circuit for CI being completed at 3K4. The only condenser now to charge is Cl. When, in due course, NI breaks down, W2 is de-ener gized, WI is energized and self-maintained, Cl ceases to charge and C4 charges. The next relay winding to be energized will be W4 and then W3 and so on, the cycle repeating itself. If desired, each relay or subsidiary relay as the case may be,'may be fitted with an extra pair of contacts connected to short circuit (when the relay winding is energized) the condenser whose discharge has occasioned energization of said relay, thus completing the discharging partly effected through the appropriate discharge lamp.

In some cases one or more of the characters in a signal to be transmitted may be of such short duration as to render it unnecessary to arrange for the corresponding relay winding to be selfmaintaining. In such a case the maintaining contacts (the Kl contacts of the accompanying Fig. 2) of the appropriate relay together with charging and breaking contacts of other relays) connected therewith may be omitted and the maintaining contacts of the next relay in the sequence may be permanently short circuited. A case of this type is illustrated in the accompanying Fig. 3 which shows a two relay combination capable'of switching a transmitter to transmit either E or T or interlocked E and T as may be required, for example, in an equi-signal blind approach .navigation aiding radio system.

In Fig. 3 the two relay windings are indicated at A and B, a discharge lamp at N, a condenser at C, and a charging resistance at R. On closing the main switch condenser C begins to charge and does so until lamp N breaks down and, in so doing, energizes winding B. This breaks the circuit of A at B2 but such interruption is only momentary for, as soon as condenser C has sufficiently discharged, winding 13 is de-energized and contacts B2 reclose. The contacts B3 shown are optional; they serve to complete discharging of condenser C. The contacts Al associated with winding A may be used for the T signal and the contacts Bl for the E signal.

In some cases it may be desired so to arrange matters that one and the same relay acts as a change-over relay to switch one signal on and the other off, instead of using (as in Fig. 1) one relay for switching oif and another for switching on. For example, the embodiment illustrated in Fig. 1 might be modified by transferring contact X4 so as to be operated by relay winding W3 (the transferred contact X4 being normally closed so that it opens when contact Y3 closes) andtransferring contact X2 to be operated by relay winding WI (the transferred contact X2 similarly opening when contact Yl closes). Again the transmitters or other signal source may be electrically interlocked in a manner similar to that which is described in my copending United States application, Serial No. 82,515 which was filed May 29, 1936. However, I now propose to omit the timing and charging circuits and to make or break a single contact on each of two alternately operable relays. Thus in Fig. 1 relays WI and W3 may be utilized to trigger the interlocking circuit. The arrangement shown in the accompanying Fig. 3 is also suitable for use in combination with the electrically interlocked valve circuits of the above mentioned co-pending application.

I claim:

1. An electrical control apparatus suitable for use for the purpose specified comprising a plurality of condensers each having its own charging circuit, means including a glow discharge tube in series with a relay winding and in shunt with each condenser for enabling an appropriate condenser to charge to a predetermined voltage in a. predetermined time, and means comprising contacts under control of each relay winding for exercising predetermined control functions, each said relay having at least two pairs of additional contacts, said additional contacts constituting holding and releasing circuit controlling means associated with the relay windings and with the glow tubes and so arranged that the respective relays and associated glow tubes are caused to be energized and de-energized in a predetermined sequence, one pair of said additional contacts being adapted to serve as holding contacts for its own relay and to de-ionize the glow tube associated therewith, and another pair of said additional contacts being adapted to release a previously energized one of said relays.

2. An electrical control apparatus suitable for use for the purpose specified comprising a plurality of condensers each having its own charging circuit, means including a glow discharge tube in series with a relay winding in shunt with each condenser for enabling .an appropriate condenser to charge to a predetermined voltage in a predetermined time, a plurality of contacts under control of each relay winding, said contacts comprising means for exercising predetermined control functions and at least three pairs of additional contacts, one of said three pairs being a normally open pair of contacts in a charging circuit for the condenseryassociated with the next relay and also in a holding circuit for the relay winding with which it is itself associated, said holding and charging circuits including a normally closed second-pair of contacts associated with the said next relay, the third pairs of contacts of all the relays being normally closed contacts connected all in series with a starting relay, the whole arrangement being characterized in that, after operation of the starting relay the condensers are enabled to charge one at a time in predetermined sequence, the completion of the charge in any one condenser to a voltage sufficient to break down the associated glow discharge lamp causing (through the energization of the associated relay) a breaking of the energizing circuit for the relay which was last energized.

3. An electrical control apparatus suitable for use for the purpose specified comprising a plurality of condensers each having its own charging circuit, meansjincluding .a glow discharge tube in series with a relay winding in shunt with each condenser for enabling an appropriate condenser to charge to a predetermined voltage in a predetermined time, a plurality of contacts under control of each relay winding, said contacts comprising means for exercising predetermined control functions and at least as many pairs of additional contacts as there are relays, one of said pairs being a normally open pair of contacts in a holding circuit for the relay winding with which it is itself associated, said holding circuit including in series a normally closed second pair of contacts associated with the next relay, a normally third closed pair of contacts associated with the next relay but one and so on, all the contacts in said series circuit being also the only contacts in a charging circuit for the condenser associated with said next relay, the whole arrangement being characterized in that, upon switching on, all the condensers are enabled to begin charging but, when one has charged sufficiently to operate its associated relay through the appropriate discharge tube, said relay operates to maintain its own circuit and break all charging circuits for all except the next condenser, the condensers and relays thereafter charging and operating in cyclic succession.

4. Apparatus for exercising predetermined control functions in timed sequence comprising a circuit arrangement including a plurality of gaseous discharge tubes each in series with the winding 'of a relay, means including a condenser in shunt with each said tube and relay winding for storing an energy charge sufiicient to proerated by each said relay for successively o'pen-' ing the circuits of the holding contact means- NEW SOME HENRY CLOUGH. 

